This Section specifies a premixed, ready to use concrete toppings for floors subjected to increased abrasion, point loading, and abuse. The material is FACTORY proportioned, mixed, and packaged by the manufacturer. Each material is scientifically blended with aggregates, cementitious binders, plasticizers, water-reducing admixtures, and other proprietary ingredients.
1.02 RELATED SECTIONS
Section 03300 - Cast in Place Concrete
American Concrete Institute (ACI)
301-89 Specification for Structural Concrete for Buildings
302.1R-99 Guide for Concrete Floor and Slab Construction
ASTM C 171-97a, Standard Specification for Sheet Materials for Curing Concrete
ASTM C 1315–00, Liquid Membrane-Forming Compounds Having Special Properties of Curing and Sealing Concrete
ASTM C 666 /666M Standard Test Method for Resistance of Concrete to Rapid Freezing and Thawing
Submit current manufacturer's product data sheets on all products to be used for the work.
Certification stating applicator is experienced in the application of the specified product.
1.05 QUALITY ASSURANCE
Pre-installation Meeting: Convene a pre-installation meeting three weeks before the start of application of the concrete topping material. Require attendance of parties directly affecting the work of this Section, including Contractor, Engineer, Architect, applicator, and manufacturer representative.
Job Mock Up: In a location designated by the Architect, place a minimum 100 square feet floor mock up using materials, procedures and personnel proposed to be used on the project. During job mock-up and initial period of installation, the manufacturer of the surface hardener will provide, at no cost, the service of a trained employee to aid in securing proper use of the product.
ACI 544.2 R89, Impact resistance. At seven day, no cracking after 4500 blows.
ASTM C 1202, Chloride Ion Penetrability Results: rating: “Very Low,” less than 1,000 coulombs passing.
ASTM C 666/666M, Freeze-Thaw Durability Factor not less than 90%
EMERY TOP 400 by Laticrete International, Inc.
Evaporation Retardant: E-CON, by Laticrete International, Inc.
Curing compound: DRESS & SEAL WB 30, by Laticrete International, Inc.
Semi-rigid Joint Filler: JOINT TITE 750, by Laticrete International, Inc.
Bonding Agent Epo Bond, by Laticrete International, Inc.
Concrete Curing Cover, Transguard 4000 by Reef industries, or Hydracure sheeting, by PNA Construction Technologies, or equal.
PART 3 - EXECUTION
3.01 CONCRETE PLACEMENT (For application over plastic concrete)
Follow ACI 302.1R-96 recommendations for placement for concrete toppings.
Placement over plastic concrete
Maximum slump of five inches (5").
Maximum air content of three percent (3%).
Do not use set accelerating admixtures, such as calcium chloride.
Verify by examination that surfaces are acceptable to receive the concrete topping. Notify the Architect immediately if surfaces are not acceptable to receive material.
Over pre-set concrete
The top surface of the concrete must be scarified and left sound but irregular, exposing the topmost surface of the coarse aggregate with a minimum amplitude of ¼ inch between peaks and valleys. The bonding agent is prepared by mixing one part by volume Everbond with one part by volume dry Portland cement. The bonding slurry is scrubbed into the surface of the substrate that is saturated surface damp (SSD) no more than 15 minutes before the placement of the concrete topping. Do not allow Everbond slurry mix to dry or puddle. [Note: The saturated surface damp (SSD) condition is best achieved by soaking the substrate for 12 hours and just prior to the placement of concrete topping.]
Over plastic concrete
Place the concrete and strike off using a vibratory screed. Fill float (bull float) immediately after strike off and before bleed water appears. After concrete bleed water has dissipated, darby or jitterbug surface to produce a mortar bed approximately ¼ in. thick, measured from the top of the coarse aggregate. Using a tine bow rake, lightly score the concrete surface at right angles to a depth of approximately 1/8 in. (Caution must be taken to not disturb coarse aggregate.) Raise the strike-off level of the vibratory screed to the specified final elevation of the concrete floor. The vibratory screed should be operating at approximately ¼ speed. Place the freshly mixed emery concrete topping on the surface of the concrete immediately ahead of the vibratory screed. Care should be taken not to exceed the screed’s capacity. The concrete topping should be approximately 1/8 in. above the bottom of the screed. Strike off the concrete topping with the vibratory screed.
NOTE: If coarse aggregate from the concrete starts to appear through the surface, lower the vibratory screed running speed or delay further placement of concrete topping until the concrete is less plastic.
Use finishing machines to compact surface by a third mechanical floating if time and setting characteristics will allow. Use L&M E-CON to reduce plastic shrinkage cracks.
As surface further stiffens, hand or mechanically trowel with raised blades to produce a dense, hard, wearing surface.
For application over pre-set concrete
Wet cure concrete topping for seven days, covering the slab with concrete curing cover materials or curing blankets. After seven days, remove cover curing, allow to dry and then continue curing with two coats of high solids, ASTM-C-1315 conforming L&M DRESS & SEAL WB 30 curing and sealing compound. Apply second coat immediately after the first coat has dried to touch, at right angles. Allow sealer to dry before opening to traffic.
For application over plastic concrete
Cure with two coats of high solids, ASTM-C-1315 conforming L&M DRESS & SEAL WB 30 curing and sealing compound. Apply second coat immediately after the first coat has dried to touch, at right angles. Allow sealer to dry before opening to traffic.
3.05 CONTROL JOINTS
Saw cut control joints as soon as the surface permits the weight of the saw without causing topping edges to ravel. If the topping is placed over pre-concrete cut the joints through the topping and into the joints of the substrate concrete.
After concrete has fully cured, fill joint wells with JOINT TITE 750, a two-component, polyurea control joint filler, according to manufacturer’s recommendations.
Cover floors and keep free of traffic and loads for a minimum of seven days after placement of heavy duty concrete topping